Classification of energy storage systems

There are several approaches to classifying energy storage systems. The most common approach is classification according to physical form of energy and basic operating principle: electric (electromagnetic), electrochemical/chemical, mechanical, thermal.

2. Energy storage system (ESS) classification Energy storage methods can be used in various applications. Some of them may be properly selected for specific applications, on the other hand, some others are frame applicable in wider frames. Inclusion into the sector of energy storage methods and technologies are intensively expected in the future.

Energy storage technologies could be classified using different aspects, such as the technical approach they take for storing energy; the types of energy they receive, store, and produce; the timescales they are best suitable for; and the capacity of storage. 1.

These classifications lead to the division of energy storage into five main types: i) mechanical energy storage, ii) chemical energy storage, iii) electrochemical energy storage, iv) electrostatic and electromagnetic energy storage, and v) thermal energy storage, as illustrated in (Figure 2).

Electricity storage systems include those that store electrical energy directly; for example, electrostatically (in capacitors) or electromagnetically (in inductors) (Kap. 6).

The most common chemical energy storage systems include hydrogen, synthetic natural gas, and solar fuel storage. Hydrogen fuel energy is a clean and abundant renewable fuel that is safe to use. The hydrogen energy can be produced from electrolysis or sunlight through photocatalytic water splitting (16,17).